Characterization of the Minimal Catalytic Domain Within EIF2B: the Guanine-nucleotide Exchange Factor for Translation Initiation
Overview
Molecular Biology
Affiliations
For protein synthesis initiation in eukaryotes, eIF2B is the guanine-nucleotide exchange factor for eIF2. eIF2B is an essential multi-subunit factor and a major target for translational control in both yeast and mammalian cells. It was shown previously that the largest eIF2B subunit, eIF2Bepsilon, is the only single subunit with catalytic function. Here we report the results of a molecular dissection of the yeast epsilon subunit encoded by GCD6 in which we have identified the catalytic domain. By analysis of a series of N-terminal deletions in vitro we find that the smallest catalytically active fragment contains residues 518-712 (termed Gcd6p(518-712)). Further deletion to position 581 (Gcd6p(581-712)) results in loss of nucleotide exchange function, but eIF2-binding activity is retained. C- terminal deletion of only 61 residues (Gcd6p(1-651)) results in loss of both functions. Thus Gcd6p(518-712) contains two regions that together constitute the catalytic domain of eIF2B. Finally, we show that the catalytic domain can provide eIF2B biological function in vivo when elevated levels eIF2 and tRNA(i)(Met) are also present.
Local mRNA translation and cytoskeletal reorganization: Mechanisms that tune neuronal responses.
Triantopoulou N, Vidaki M Front Mol Neurosci. 2022; 15:949096.
PMID: 35979146 PMC: 9376447. DOI: 10.3389/fnmol.2022.949096.
Zheng H, Ma L, Gui R, Lin X, Ke X, Jian X J Virol. 2022; 96(12):e0049422.
PMID: 35604143 PMC: 9215228. DOI: 10.1128/jvi.00494-22.
Friedrich D, Marintchev A, Arthanari H Nucleic Acids Res. 2022; 50(10):5424-5442.
PMID: 35552740 PMC: 9177959. DOI: 10.1093/nar/gkac342.
GTP binding to translation factor eIF2B stimulates its guanine nucleotide exchange activity.
Kershaw C, Jennings M, Cortopassi F, Guaita M, Al-Ghafli H, Pavitt G iScience. 2021; 24(12):103454.
PMID: 34877508 PMC: 8633983. DOI: 10.1016/j.isci.2021.103454.
Early Changes in Skeletal Muscle of Young C22 Mice, A Model of Charcot-Marie-Tooth 1A.
Deres F, Schwartz S, Kappes-Horn K, Kornblum C, Reimann J J Neuromuscul Dis. 2021; 8(s2):S283-S299.
PMID: 34459411 PMC: 8673495. DOI: 10.3233/JND-210681.